Canvas HTML5 JavaScript代码不工作,带有Canvas.toDataURL()
我无法使此代码正常工作:Canvas HTML5 JavaScript代码不工作,带有Canvas.toDataURL(),javascript,html,canvas,Javascript,Html,Canvas,我无法使此代码正常工作: (function() { // Creates a new canvas element and appends it as a child // to the parent element, and returns the reference to // the newly created canvas element function createCanvas(parent, width, height) { v
(function() {
// Creates a new canvas element and appends it as a child
// to the parent element, and returns the reference to
// the newly created canvas element
function createCanvas(parent, width, height) {
var canvas = {};
canvas.node = document.createElement('canvas');
canvas.context = canvas.node.getContext('2d');
canvas.node.width = width || 100;
canvas.node.height = height || 100;
parent.appendChild(canvas.node);
return canvas;
}
function init(container, width, height, fillColor) {
var canvas = createCanvas(container, width, height);
var ctx = canvas.context;
// define a custom fillCircle method
ctx.fillCircle = function(x, y, radius, fillColor) {
this.fillStyle = fillColor;
this.beginPath();
this.moveTo(x, y);
this.arc(x, y, radius, 0, Math.PI * 2, false);
this.fill();
};
ctx.clearTo = function(fillColor) {
ctx.fillStyle = fillColor;
ctx.fillRect(0, 0, width, height);
};
ctx.clearTo(fillColor || "#ddd");
// bind mouse events
canvas.node.onmousemove = function(e) {
if (!canvas.isDrawing) {
return;
}
var x = e.pageX - this.offsetLeft;
var y = e.pageY - this.offsetTop;
var radius = 10; // or whatever
var fillColor = '#ff0000';
ctx.fillCircle(x, y, radius, fillColor);
};
canvas.node.onmousedown = function(e) {
canvas.isDrawing = true;
};
canvas.node.onmouseup = function(e) {
canvas.isDrawing = false;
};
}
var container = document.getElementById('canvas');
init(container, 200, 200, '#ddd');
})();
function hi(){
var canvas = document.getElementsByTagName('canvas');
var imageData = canvas.toDataURL();
document.getElementById("his").innerHTML=imageData;
}
这是一个小JavaScript代码,它使用canvas
的id
在div
中创建一个小画布
而且,我正在尝试保存图像,并使用
his
保存图像的id
将图像写入div
。现在这就是代码停止工作的地方。。。非常感谢您的帮助,谢谢!:) 图像数据URL属于图像src
属性。图像没有innerHTML
图像数据URL属于图像src
属性。图像没有innerHTML
返回节点列表,而不是单个元素。所以使用
function hi(){
var canvas = document.getElementsByTagName('canvas')[0];
imageData = canvas ? canvas.toDataURL() : "could not find a <canvas> element";
document.getElementById("his").textContent = imageData;
}
函数hi(){
var canvas=document.getElementsByTagName('canvas')[0];
imageData=canvas?canvas.toDataURL():“找不到元素”;
document.getElementById(“his”).textContent=imageData;
}
返回一个节点列表,而不是单个元素。所以使用
function hi(){
var canvas = document.getElementsByTagName('canvas')[0];
imageData = canvas ? canvas.toDataURL() : "could not find a <canvas> element";
document.getElementById("his").textContent = imageData;
}
函数hi(){
var canvas=document.getElementsByTagName('canvas')[0];
imageData=canvas?canvas.toDataURL():“找不到元素”;
document.getElementById(“his”).textContent=imageData;
}
为什么要将URL输出为innerHTML
?@bergi我以为它的URL可以用纯文本访问。是的,它是,虽然你最好使用.textContent
来实现这一点。什么.textContent
?看看你为什么要将URL输出为innerHTML
?@bergi我认为它的URL可以用纯文本访问。是的,它是,虽然你最好使用.textContent
来实现这一点。什么.textContent
?看,我认为它的URL可以用纯文本访问。我认为它的URL可以用纯文本访问。当我完全按照你在示例中所做的做时,我得到了这个::别忘了检查你的错误控制台!所以出了什么问题@请看链接问题的答案!当我完全按照您在示例中所做的操作时,我得到了以下信息::别忘了检查您的错误控制台!所以出了什么问题@请看链接问题的答案!